Clearly a mission president effect is observed, note the color changes and regression lines by mission president for each mission.
However we should confirm that the mission president effect isn’t overly influenced/confounded by the number of missionaries. The plot below confirms that the mission president has a potentially strong effect on the number of new investigators within a mission.
Again a mission president effect is observed.
Outliers are possible and we would want to be careful about their effect on predictions/goals.
Quote from Preach My Gospel about goals and how that influenced my suggestions regarding mission goals
Incorporate a machine learning model or time-series model for prediction.